The present invention relates to a flap type indicating device and, more particularly, to a synchronizing mechanism for changing in synchronism with each other the indications in two series of indications in a flap type indicating device having a low speed rotative flap type indicating assembly adapted to exhibit a first series of indications upon one revolution thereof and a high speed rotative flap type indicating assembly adapted to exhibit a second series of indications upon one revolution thereof, the respective indication of said first series being determined to be switched successively to the next indication each time said second series of indication has been completed.
A prior art synchronizing mechanism in a flap type indicating device of the type as described above such as that embodied in a flap type digital clock which includes a plurality of hour drums so as to indicate successively the time in terms of hour by the respective flaps as the same are swung successively during one complete revolution of the hour drum by disengagement of the flap from a holding member adapted to temporarily arrest the respective flaps and a plurality of minute flaps swingably mounted in series along the periphery of a minute drum coaxially arranged with the hour drum so as to indicate successively the time in terms of minute by the respective flaps as the same are swung successively during one complete revolution of the minute drum by disengagement of the flap from a holding member adapted to temporarily arrest the respective flaps is determined to insure that the hour flap such as indicating 4 o'clock, for example, is positively swung so as to indicate the next indication, i.e., 5 o'clock, when the minute flap indicating 59 minute is swung so as to indicate the next indication of 00 minute so that false indication such as 4 o'clock 00 minute or 5 o'clock 59 minute is positively prevented after the time 4 o'clock 59 minute lapses.
In such a prior art synchronizing mechanism as described above, a lug is formed in each of the minute flaps indicating respectively from 45 minute to 59 minute, while a resilient synchronizing member is interposed between the hour flaps and the minute flaps so as to be actuated by the lug of the respective flaps to move into the path of movement of the hour flaps for temporarily arresting the hour flap then positioned to be swung for the next indication during the rotation of the hour drum, and the time the holding member for temporarily arresting the hour flap then positioned to be swung for the next indication is disengaged therefrom is set to be earlier than the time at which the minute flap indicating 59 minute is disengaged from the holding member temporarily arresting the same so as to complete one cycle of the series of minute indications, the synchronizing member being so configured that the lug of the minute flap indicating 45 minute actuates the synchronizing member during the rotation of the minute drum before the hour flap then positioned to be swung for the next indication is disengaged from the holding member therefor, so that the hour flap then positioned to be swung for the next indication is held at its indicating position until the minute flap indicating 59 minute is swung to switch to 00 minute and disengages the lug thereof from the synchronizing member to swing the hour flap for the next indication even though the holding member for hour flaps has been disengaged from the respective hour flap, thereby insuring the synchronized operation of the respective hour flap and the minute flap indicating 59 minute.
In this case, if the clock is designed to indicate 24 hours, the hour drum is rotated by one revolution in 24 hours, whereas the hour drum is rotated by one revolution, if the clock is designed to indicate 12 hours. At any rate, the rotative speed, i.e., the amount of revolution of the hour drum per hour is extremely low and, therefore, it is made very difficult to exactly set the time at which the respective hour flap is disengaged from the holding member therefor for the next indication in synchronism with the switching of minute indication from 59 minute to 00 minute, because very high machining accuracy of the parts and accurate assembly thereof are required so as to obtain the desired result. Thus, the lugs are formed in minute flaps indicating respectively 45 minute to 59 minute so as to cooperate with the synchronizing member for insuring the synchronized operation of the hour and minute flaps as described above.
In making the flaps, as is evident, press dies and punches for making the flaps having the lugs are very difficult to be manufactured in comparison with those for making the flaps without any lugs, while the lugs of the flaps are liable to be deformed or damaged during the manufacture and the assembly of the flaps, therefore, necessity of using large number of flaps having the lugs in the prior art has caused difficulties in the manufacture of flap type indicating devices.